The present invention relates generally to archery and, more particularly, to an arrow rest for use in conjunction with an archery bow.
An arrow rest, which is an add-on device that is located near the midpoint of an archery bow, provides support for a nocked arrow. Ideally, the arrow rest should position the arrow in a reproducible manner and should not impede or otherwise alter its flight following release. But certain events occur during shooting that makes this ideal difficult to attain.
In particular, the flight of an arrow can be altered after release as a result of certain types of contact between it and the arrow rest. For example, forces are imparted to an arrow during release that cause it to flex. These forces are primarily vertically directed for shooters that use a mechanical release aid (xe2x80x9crelease shootersxe2x80x9d) and primarily horizontally directed for shooters that do not use a release aid (xe2x80x9cfinger shootersxe2x80x9d). If the arrow rest is not designed to compliantly receive these forces, a flight-altering bounce of the arrow results. Furthermore, contact between the fletchings or vanes of the arrow and the arrow rest affects the arrow""s flight. Both of these conditions decrease shooting accuracy.
The art is replete with arrow-rest designs. Many of these designs seek to decrease the deflection of a released arrow to improve shooting accuracy. Notwithstanding any structural differences among these designs, most known arrow rests have certain features in commonxe2x80x94features that can limit their effectiveness. Specifically, most known designs incorporate one or more of the following components:
a pivoting arm to provide compliance;
bearings for smooth motion of the pivoting arm;
a mechanical spring to impart resilience to the pivoting arm;
a stop to limit travel of the pivoting arm.
In most arrow rests that have a movable arm, the arm pivots about an axis. One disadvantage of pivoting arms is that they typically are compliant (i.e., provide for movement) in only one directionxe2x80x94usually the vertical direction (i.e., movement in a plane that is parallel to the handle-riser portion of the bow), as they pivot about a horizontal axis. This limits the desirability of the arrow rest for finger shooters, who tend to impart forces that require compliance in the horizontal direction. In fact, it is generally understood that both finger and release shooters would benefit from an arrow rest that is compliant in two directions: vertical and horizontal.
Pivoting arms typically use bearings (e.g., ball, sleeve, etc.) to provide smooth motion. But a disadvantage of bearings is that they introduce xe2x80x9cplayxe2x80x9d into the arm, often as much as {fraction (1/16)}th of an inch, thereby decreasing shooting accuracy.
A disadvantage of a mechanical spring, which is often used to impart resilience (i.e., elastic behavior) to the pivoting arm, is that it exhibits xe2x80x9chysteresis.xe2x80x9d That is, as the spring ages, its behavior (i.e., the spring constant) changes, so that the spring might not be able to return the pivoting arm to its original position. Failure to position the arrow shaft in a reproducible manner can affect shooting accuracy.
A further disadvantage of a mechanical spring for this use is that it has a restoring force that increases with increasing displacement. Due to this characteristic, as a pivoting arm that is biased by a mechanical spring moves relatively further from its rest position (i.e., in reaction to a relatively greater force imparted by the arrow), a relatively greater restoring force is experienced. In contrast, it is generally accepted that a fall-away motion, wherein the restoring force decreases with increasing displacement, is preferable.
Another disadvantage of a mechanical spring for this use is that it typically requires the use of a xe2x80x9cstop.xe2x80x9d After the movable arm has pivoted downward in response to an impulse from an arrow, the arm is accelerated back (toward its rest position) due to the action of the mechanical spring (i.e., resilience). The stop abruptly settles (i.e., stops) the arm at its rest position. The abrupt fashion in which the arm is stopped can introduce noise, which is anathema to a bow hunter.
So, despite the large number of arrow rests that are available, most exhibit one or more disadvantages as described above. A need therefore remains for an arrow rest that overcomes or at least ameliorates one or more of the foregoing shortcomings toward the end of achieving the ideal of reproducible arrow positioning and true flight.
In accordance with the present invention, an arrow rest is disclosed that avoids at least some of the disadvantages of known arrow rests. Some arrow rests in accordance with the illustrative embodiment of the invention:
do not include an arm that pivots about an axis;
do not use bearings;
do not use a mechanical spring; and
do not use a stop.
Some arrow rests in accordance with the illustrative embodiment include a shuttle, a cradle and a bow-connecting member. The shuttle, which supports a nocked arrow, is mechanically and magnetically coupled to the cradle. The cradle, in turn, is connected to an archery bow by the bow-connecting member.
The shuttle is mechanically coupled to the cradle in such a way that the shuttle has some freedom to move or xe2x80x9cglidexe2x80x9d in two dimensions that are generally orthogonal to the axis of the arrow.
The magnetic coupling between the shuttle and the cradle imparts resilience to the shuttle. Arrow rests in accordance with the illustrative embodiment are advantageously resilient vertically and horizontally in a plane. Furthermore, since resilience is provided by magnetic interaction, wherein the force of attraction decreases with increasing distance, arrow rests in accordance with the illustrative embodiment are advantageously configured to exhibit xe2x80x9cfall-awayxe2x80x9d motion. By adjusting the strength of the magnetic interaction, such as by altering the distance between the materials that are magnetically interacting, the arrow rest can be tailored to an archer""s shooting style.
The illustrative embodiment described above, and some variations thereof, are illustrated in the Drawings and described further in the Detailed Description section of this specification.